1. Field of the Invention
The present invention relates in general to a photographic camera having an automatic focus adjusting or focus apparatus (which will be referred to simply as AF camera hereinafter), and in particular concerns a manual focus setting apparatus for AF cameras which allows the focal point to be set manually independently from a ranging apparatus adapted to measure distance to an object to be photographed for the automatic focal adjustment.
2. Description of the Prior Art
There has been hitherto known the AF camera in which a lens barrel provided with a helicoid screw for effecting the movement of a focusing lens along the optical axis thereof, and a focusing ring interlocked with the lens barrel and meshed with a gear for controlling the movement of the focusing lens as well as an actuator member provided with ratchet gear means for controlling rotation thereof in cooperation with a ratchet in response to operation of an electro-magnet are drived in one direction by driving means such as springs, wherein the movement of the actuator member is stopped through engagement of the ratchet with the ratchet gear means, which ratchet in turn is operated by the electro-magnet controlled by a focusing signal produced from the ranging device when the distance to the object to be photographed is detected as the result of the ranging scanning operation in correspondence to the movement of the focusing lens, thereby to effect automatically the focal adjustment of the focusing lens. With such AF camera, photographs focused to the aimed objects can be conveniently taken without requiring focusing manipulations on the basis of the judgement of the user. However, in the case where a unique effect is to be produced by making use of the out-of-focus condition (defocused condition) intentionally in accordance with a mind of user or when the object to be photographed is overcapability of the ranging device (i.e. the device for measuring distance to the object) such as objects of low contrast or such as objects of a repetition of simple identical patterns, for example, there may arise a problem that the focal point can not be automatically set in accordance with the distance to the object to be photographed.